The usefulness of photoconductive devices is well understood by those possessing an ordinary skill in the pertinent arts. For example, photoconductive surfaces may be used to create images by xerography. Typical devices that employ xerography include commercially available photocopiers, laser printers and facsimile machines, for example. Photoconductive devices use photoconductive materials whose operational characteristics, such as electrical conductivity, is affected by exposure to electromagnetic radiation, such as light. One example of such a photoconductive material is an organic photosensitive material, such as polycarbonate dissipated with optically conductive resin.
Generally, a photoconductive device, such as a laser based printer or facsimile machine, uses a Light Amplification by Stimulated Emission of Radiation (LASER) device to illuminate select portions of a photoconductive surface, commonly referred to as a drum, in such a way as to be representing an image to be produced. Such illumination may be effected by scanning the laser device across the imaging surface of the drum. Alternatively, for example, the drum may be illuminated using an array of Light Emitting Diode (LED) devices. Regardless, select portions of the drum corresponding to areas to be imaged are conventionally illuminated, within the visible spectrum, for example.
Electrical charge on the illuminated portions of the drum are effected, e.g., charged, as is well understood by those possessing an ordinary skill in the pertinent arts, as compared to non-illuminated portions of the drum, for example—thus creating an electrostatic latent image on the drum surface. The drum may then be rolled through a reservoir of toner such that toner adheres, via electrostatic adhesion for example, to those portions of the drum that have been charged. The adhering toner may then be transferred to a substrate, such as a sheet of paper, using conventional methodologies—by applying heat and pressure to the toner and/or substrate for example, thus producing desired images on the substrate.
There are, however, many problems with conventional photoconductive devices. In particular, conventional devices are costly to manufacture. Thus, there currently is a need to make photoconductive devices cheaper to manufacture by, for example, eliminating a number of parts that are commonly required. Conventional photoconductive devices also have limitations in terms of imaging speeds. As such, it is similarly desirable to increase the imaging speed of such devices. Lastly, conventional photoconductive devices can be large and bulky. Therefore, photoconductive devices which are reduced in size are desirable as well.